Performance and Stability Analysis for ZJU Glider

Underwater gliders provide an effective, low-cost method for sampling the ocean over large spatial and temporal scales. In this paper, we present a series of theoretical analyses to provide guidelines for vehicle design, which are used to develop a coastal 200-m-depth underwater glider known as the Zhejiang University (ZJU) glider. The ZJU glider uses a longitudinally actuated moving mass for pitch control and a rudder for turning control. Computational methods and analytical approaches are chosen to solve the viscous and inviscid terms of glider hydrodynamics, respectively. Steady flight equilibrium analysis gives the varied range of moving mass location for pitch control and varied vehicle volume for buoyancy control. Size analysis investigates the effects of glider geometric parameters on motion performance. For wings-level flight, we describe the variation in the maximum lift-to-drag ratio corresponding to a given vehicle size and speed. For turning motion, we investigate the manner in which the turning performance varies with vertical rudder configuration. Stability analysis determines the relationship between the stability of glider motion and the locations of the glider wings and rudder. Pool trials indicate that the ZJU glider functions well in water and is capable of serving as a sensor platform for ocean sampling.